An interlocking panel truck bed liner comprises a horizontal grid base formed in a solid planar rectangular configuration. The base has an upper surface and a lower surface. The lower surface includes coupling devices to permit affixation to the floor of a truck bed. The upper surface has a plurality of perpendicularly intersecting, rectangular-shaped horizontal grooves. Four vertical sidewall liners are each formed in a solid planar rectangular configuration with a front surface and a rear surface. The rear surface of each sidewall liner includes coupling devices to permit vertical affixation to the sidewalls and tailgate of a truck. The front surface of each sidewall liner includes vertical grooves positioned in alignment with the grooves in the grid base. A plurality of interlocking panels are each formed in a planar rectangular configuration. Each panel has two identical surfaces. The panels are positioned vertically in an operative orientation and include a plurality of coupling devices. The panels are adapted to couple to each other in parallel and perpendicular orientations. The panels are positioned within the grooves of the sidewall liners and grid base in an operative orientation.